The person who founded Qihoo 360， Hongwei Zhou（周鸿祎）, is the creator of the
malware named 3721. 3721 is the most widely spread malware in China before the
company Qihoo 360 was founded. The reason that "360安全卫士" (360 Total Security),
which is the most important product of Qihoo 360, became popular is that it was
the best software to remove malwares, especially 3721. As the creator of the
most widely spread malware, it is not surprising 360 Total Security works well
at removing malwares. However, I will never trust a security software made by
the one made a malware. Just like I will never hire a guard that was a thief.